text: /*
   * WPA Supplicant / shared MSCHAPV2 helper functions / RFC 2433 / RFC 2759
   * Copyright (c) 2004-2009, Jouni Malinen <j@w1.fi>
   *
   * This software may be distributed under the terms of the BSD license.
   * See README for more details.
   */
  
  #include "includes.h"
  
  #include "common.h"
  #include "sha1.h"
  #include "ms_funcs.h"
  #include "crypto.h"
  
  /**
   * utf8_to_ucs2 - Convert UTF-8 string to UCS-2 encoding
   * @utf8_string: UTF-8 string (IN)
   * @utf8_string_len: Length of utf8_string (IN)
   * @ucs2_buffer: UCS-2 buffer (OUT)
   * @ucs2_buffer_size: Length of UCS-2 buffer (IN)
   * @ucs2_string_size: Number of 2-byte words in the resulting UCS-2 string
   * Returns: 0 on success, -1 on failure
   */
  static int utf8_to_ucs2(const u8 *utf8_string, size_t utf8_string_len,
                          u8 *ucs2_buffer, size_t ucs2_buffer_size,
                          size_t *ucs2_string_size)
  {
  	size_t i, j;
  
  	for (i = 0, j = 0; i < utf8_string_len; i++) {
  		u8 c = utf8_string[i];
  		if (j >= ucs2_buffer_size) {
  			/* input too long */
  			return -1;
  		}
  		if (c <= 0x7F) {
  			WPA_PUT_LE16(ucs2_buffer + j, c);
  			j += 2;
  		} else if (i == utf8_string_len - 1 ||
  			   j >= ucs2_buffer_size - 1) {
  			/* incomplete surrogate */
  			return -1;
  		} else {
  			u8 c2 = utf8_string[++i];
  			if ((c & 0xE0) == 0xC0) {
  				/* two-byte encoding */
  				WPA_PUT_LE16(ucs2_buffer + j,
  					     ((c & 0x1F) << 6) | (c2 & 0x3F));
  				j += 2;
  			} else if (i == utf8_string_len ||
  				   j >= ucs2_buffer_size - 1) {
  				/* incomplete surrogate */
  				return -1;
  			} else {
  				/* three-byte encoding */
  				u8 c3 = utf8_string[++i];
  				WPA_PUT_LE16(ucs2_buffer + j,
  					     ((c & 0xF) << 12) |
  					     ((c2 & 0x3F) << 6) | (c3 & 0x3F));
  			}
  		}
  	}
  
  	if (ucs2_string_size)
  		*ucs2_string_size = j / 2;
  	return 0;
  }
  
  
  /**
   * challenge_hash - ChallengeHash() - RFC 2759, Sect. 8.2
   * @peer_challenge: 16-octet PeerChallenge (IN)
   * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
   * @username: 0-to-256-char UserName (IN)
   * @username_len: Length of username
   * @challenge: 8-octet Challenge (OUT)
   * Returns: 0 on success, -1 on failure
   */
  static int challenge_hash(const u8 *peer_challenge, const u8 *auth_challenge,
  			  const u8 *username, size_t username_len,
  			  u8 *challenge)
  {
  	u8 hash[SHA1_MAC_LEN];
  	const unsigned char *addr[3];
  	size_t len[3];
  
  	addr[0] = peer_challenge;
  	len[0] = 16;
  	addr[1] = auth_challenge;
  	len[1] = 16;
  	addr[2] = username;
  	len[2] = username_len;
  
  	if (sha1_vector(3, addr, len, hash))
  		return -1;
  	os_memcpy(challenge, hash, 8);
  	return 0;
  }
  
  
  /**
   * nt_password_hash - NtPasswordHash() - RFC 2759, Sect. 8.3
   * @password: 0-to-256-unicode-char Password (IN; UTF-8)
   * @password_len: Length of password
   * @password_hash: 16-octet PasswordHash (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int nt_password_hash(const u8 *password, size_t password_len,
  		      u8 *password_hash)
  {
  	u8 buf[512], *pos;
  	size_t len, max_len;
  
  	max_len = sizeof(buf);
  	if (utf8_to_ucs2(password, password_len, buf, max_len, &len) < 0)
  		return -1;
  
  	len *= 2;
  	pos = buf;
  	return md4_vector(1, (const u8 **) &pos, &len, password_hash);
  }
  
  
  /**
   * hash_nt_password_hash - HashNtPasswordHash() - RFC 2759, Sect. 8.4
   * @password_hash: 16-octet PasswordHash (IN)
   * @password_hash_hash: 16-octet PasswordHashHash (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int hash_nt_password_hash(const u8 *password_hash, u8 *password_hash_hash)
  {
  	size_t len = 16;
  	return md4_vector(1, &password_hash, &len, password_hash_hash);
  }
  
  
  /**
   * challenge_response - ChallengeResponse() - RFC 2759, Sect. 8.5
   * @challenge: 8-octet Challenge (IN)
   * @password_hash: 16-octet PasswordHash (IN)
   * @response: 24-octet Response (OUT)
   */
  void challenge_response(const u8 *challenge, const u8 *password_hash,
  			u8 *response)
  {
  	u8 zpwd[7];
  	des_encrypt(challenge, password_hash, response);
  	des_encrypt(challenge, password_hash + 7, response + 8);
  	zpwd[0] = password_hash[14];
  	zpwd[1] = password_hash[15];
  	os_memset(zpwd + 2, 0, 5);
  	des_encrypt(challenge, zpwd, response + 16);
  }
  
  
  /**
   * generate_nt_response - GenerateNTResponse() - RFC 2759, Sect. 8.1
   * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
   * @peer_challenge: 16-octet PeerChallenge (IN)
   * @username: 0-to-256-char UserName (IN)
   * @username_len: Length of username
   * @password: 0-to-256-unicode-char Password (IN; UTF-8)
   * @password_len: Length of password
   * @response: 24-octet Response (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int generate_nt_response(const u8 *auth_challenge, const u8 *peer_challenge,
  			 const u8 *username, size_t username_len,
  			 const u8 *password, size_t password_len,
  			 u8 *response)
  {
  	u8 challenge[8];
  	u8 password_hash[16];
  
  	challenge_hash(peer_challenge, auth_challenge, username, username_len,
  		       challenge);
  	if (nt_password_hash(password, password_len, password_hash))
  		return -1;
  	challenge_response(challenge, password_hash, response);
  	return 0;
  }
  
  
  /**
   * generate_nt_response_pwhash - GenerateNTResponse() - RFC 2759, Sect. 8.1
   * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
   * @peer_challenge: 16-octet PeerChallenge (IN)
   * @username: 0-to-256-char UserName (IN)
   * @username_len: Length of username
   * @password_hash: 16-octet PasswordHash (IN)
   * @response: 24-octet Response (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int generate_nt_response_pwhash(const u8 *auth_challenge,
  				const u8 *peer_challenge,
  				const u8 *username, size_t username_len,
  				const u8 *password_hash,
  				u8 *response)
  {
  	u8 challenge[8];
  
  	if (challenge_hash(peer_challenge, auth_challenge,
  			   username, username_len,
  			   challenge))
  		return -1;
  	challenge_response(challenge, password_hash, response);
  	return 0;
  }
  
  
  /**
   * generate_authenticator_response_pwhash - GenerateAuthenticatorResponse() - RFC 2759, Sect. 8.7
   * @password_hash: 16-octet PasswordHash (IN)
   * @nt_response: 24-octet NT-Response (IN)
   * @peer_challenge: 16-octet PeerChallenge (IN)
   * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
   * @username: 0-to-256-char UserName (IN)
   * @username_len: Length of username
   * @response: 20-octet AuthenticatorResponse (OUT) (note: this value is usually
   * encoded as a 42-octet ASCII string (S=hexdump_of_response)
   * Returns: 0 on success, -1 on failure
   */
  int generate_authenticator_response_pwhash(
  	const u8 *password_hash,
  	const u8 *peer_challenge, const u8 *auth_challenge,
  	const u8 *username, size_t username_len,
  	const u8 *nt_response, u8 *response)
  {
  	static const u8 magic1[39] = {
  		0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
  		0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
  		0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
  		0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74
  	};
  	static const u8 magic2[41] = {
  		0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
  		0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
  		0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
  		0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
  		0x6E
  	};
  
  	u8 password_hash_hash[16], challenge[8];
  	const unsigned char *addr1[3];
  	const size_t len1[3] = { 16, 24, sizeof(magic1) };
  	const unsigned char *addr2[3];
  	const size_t len2[3] = { SHA1_MAC_LEN, 8, sizeof(magic2) };
  
  	addr1[0] = password_hash_hash;
  	addr1[1] = nt_response;
  	addr1[2] = magic1;
  
  	addr2[0] = response;
  	addr2[1] = challenge;
  	addr2[2] = magic2;
  
  	if (hash_nt_password_hash(password_hash, password_hash_hash))
  		return -1;
  	if (sha1_vector(3, addr1, len1, response))
  		return -1;
  
  	challenge_hash(peer_challenge, auth_challenge, username, username_len,
  		       challenge);
  	return sha1_vector(3, addr2, len2, response);
  }
  
  
  /**
   * generate_authenticator_response - GenerateAuthenticatorResponse() - RFC 2759, Sect. 8.7
   * @password: 0-to-256-unicode-char Password (IN; UTF-8)
   * @password_len: Length of password
   * @nt_response: 24-octet NT-Response (IN)
   * @peer_challenge: 16-octet PeerChallenge (IN)
   * @auth_challenge: 16-octet AuthenticatorChallenge (IN)
   * @username: 0-to-256-char UserName (IN)
   * @username_len: Length of username
   * @response: 20-octet AuthenticatorResponse (OUT) (note: this value is usually
   * encoded as a 42-octet ASCII string (S=hexdump_of_response)
   * Returns: 0 on success, -1 on failure
   */
  int generate_authenticator_response(const u8 *password, size_t password_len,
  				    const u8 *peer_challenge,
  				    const u8 *auth_challenge,
  				    const u8 *username, size_t username_len,
  				    const u8 *nt_response, u8 *response)
  {
  	u8 password_hash[16];
  	if (nt_password_hash(password, password_len, password_hash))
  		return -1;
  	return generate_authenticator_response_pwhash(
  		password_hash, peer_challenge, auth_challenge,
  		username, username_len, nt_response, response);
  }
  
  
  /**
   * nt_challenge_response - NtChallengeResponse() - RFC 2433, Sect. A.5
   * @challenge: 8-octet Challenge (IN)
   * @password: 0-to-256-unicode-char Password (IN; UTF-8)
   * @password_len: Length of password
   * @response: 24-octet Response (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int nt_challenge_response(const u8 *challenge, const u8 *password,
  			  size_t password_len, u8 *response)
  {
  	u8 password_hash[16];
  	if (nt_password_hash(password, password_len, password_hash))
  		return -1;
  	challenge_response(challenge, password_hash, response);
  	return 0;
  }
  
  
  /**
   * get_master_key - GetMasterKey() - RFC 3079, Sect. 3.4
   * @password_hash_hash: 16-octet PasswordHashHash (IN)
   * @nt_response: 24-octet NTResponse (IN)
   * @master_key: 16-octet MasterKey (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int get_master_key(const u8 *password_hash_hash, const u8 *nt_response,
  		   u8 *master_key)
  {
  	static const u8 magic1[27] = {
  		0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
  		0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
  		0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79
  	};
  	const unsigned char *addr[3];
  	const size_t len[3] = { 16, 24, sizeof(magic1) };
  	u8 hash[SHA1_MAC_LEN];
  
  	addr[0] = password_hash_hash;
  	addr[1] = nt_response;
  	addr[2] = magic1;
  
  	if (sha1_vector(3, addr, len, hash))
  		return -1;
  	os_memcpy(master_key, hash, 16);
  	return 0;
  }
  
  
  /**
   * get_asymetric_start_key - GetAsymetricStartKey() - RFC 3079, Sect. 3.4
   * @master_key: 16-octet MasterKey (IN)
   * @session_key: 8-to-16 octet SessionKey (OUT)
   * @session_key_len: SessionKeyLength (Length of session_key) (IN)
   * @is_send: IsSend (IN, BOOLEAN)
   * @is_server: IsServer (IN, BOOLEAN)
   * Returns: 0 on success, -1 on failure
   */
  int get_asymetric_start_key(const u8 *master_key, u8 *session_key,
  			    size_t session_key_len, int is_send,
  			    int is_server)
  {
  	static const u8 magic2[84] = {
  		0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
  		0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
  		0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
  		0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
  		0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
  		0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
  		0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
  		0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
  		0x6b, 0x65, 0x79, 0x2e
  	};
  	static const u8 magic3[84] = {
  		0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
  		0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
  		0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
  		0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
  		0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
  		0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
  		0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
  		0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
  		0x6b, 0x65, 0x79, 0x2e
  	};
  	static const u8 shs_pad1[40] = {
  		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  	};
  
  	static const u8 shs_pad2[40] = {
  		0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
  		0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
  		0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
  		0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
  	};
  	u8 digest[SHA1_MAC_LEN];
  	const unsigned char *addr[4];
  	const size_t len[4] = { 16, 40, 84, 40 };
  
  	addr[0] = master_key;
  	addr[1] = shs_pad1;
  	if (is_send) {
  		addr[2] = is_server ? magic3 : magic2;
  	} else {
  		addr[2] = is_server ? magic2 : magic3;
  	}
  	addr[3] = shs_pad2;
  
  	if (sha1_vector(4, addr, len, digest))
  		return -1;
  
  	if (session_key_len > SHA1_MAC_LEN)
  		session_key_len = SHA1_MAC_LEN;
  	os_memcpy(session_key, digest, session_key_len);
  	return 0;
  }
  
  
  #define PWBLOCK_LEN 516
  
  /**
   * encrypt_pw_block_with_password_hash - EncryptPwBlockWithPasswordHash() - RFC 2759, Sect. 8.10
   * @password: 0-to-256-unicode-char Password (IN; UTF-8)
   * @password_len: Length of password
   * @password_hash: 16-octet PasswordHash (IN)
   * @pw_block: 516-byte PwBlock (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int encrypt_pw_block_with_password_hash(
  	const u8 *password, size_t password_len,
  	const u8 *password_hash, u8 *pw_block)
  {
  	size_t ucs2_len, offset;
  	u8 *pos;
  
  	os_memset(pw_block, 0, PWBLOCK_LEN);
  
  	if (utf8_to_ucs2(password, password_len, pw_block, 512, &ucs2_len) < 0)
  		return -1;
  
  	if (ucs2_len > 256)
  		return -1;
  
  	offset = (256 - ucs2_len) * 2;
  	if (offset != 0) {
  		os_memmove(pw_block + offset, pw_block, ucs2_len * 2);
  		if (os_get_random(pw_block, offset) < 0)
  			return -1;
  	}
  	/*
  	 * PasswordLength is 4 octets, but since the maximum password length is
  	 * 256, only first two (in little endian byte order) can be non-zero.
  	 */
  	pos = &pw_block[2 * 256];
  	WPA_PUT_LE16(pos, password_len * 2);
  	rc4_skip(password_hash, 16, 0, pw_block, PWBLOCK_LEN);
  	return 0;
  }
  
  
  /**
   * new_password_encrypted_with_old_nt_password_hash - NewPasswordEncryptedWithOldNtPasswordHash() - RFC 2759, Sect. 8.9
   * @new_password: 0-to-256-unicode-char NewPassword (IN; UTF-8)
   * @new_password_len: Length of new_password
   * @old_password: 0-to-256-unicode-char OldPassword (IN; UTF-8)
   * @old_password_len: Length of old_password
   * @encrypted_pw_block: 516-octet EncryptedPwBlock (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int new_password_encrypted_with_old_nt_password_hash(
  	const u8 *new_password, size_t new_password_len,
  	const u8 *old_password, size_t old_password_len,
  	u8 *encrypted_pw_block)
  {
  	u8 password_hash[16];
  
  	if (nt_password_hash(old_password, old_password_len, password_hash))
  		return -1;
  	if (encrypt_pw_block_with_password_hash(new_password, new_password_len,
  						password_hash,
  						encrypted_pw_block))
  		return -1;
  	return 0;
  }
  
  
  /**
   * nt_password_hash_encrypted_with_block - NtPasswordHashEncryptedWithBlock() - RFC 2759, Sect 8.13
   * @password_hash: 16-octer PasswordHash (IN)
   * @block: 16-octet Block (IN)
   * @cypher: 16-octer Cypher (OUT)
   */
  void nt_password_hash_encrypted_with_block(const u8 *password_hash,
  					   const u8 *block, u8 *cypher)
  {
  	des_encrypt(password_hash, block, cypher);
  	des_encrypt(password_hash + 8, block + 7, cypher + 8);
  }
  
  
  /**
   * old_nt_password_hash_encrypted_with_new_nt_password_hash - OldNtPasswordHashEncryptedWithNewNtPasswordHash() - RFC 2759, Sect. 8.12
   * @new_password: 0-to-256-unicode-char NewPassword (IN; UTF-8)
   * @new_password_len: Length of new_password
   * @old_password: 0-to-256-unicode-char OldPassword (IN; UTF-8)
   * @old_password_len: Length of old_password
   * @encrypted_password_hash: 16-octet EncryptedPasswordHash (OUT)
   * Returns: 0 on success, -1 on failure
   */
  int old_nt_password_hash_encrypted_with_new_nt_password_hash(
  	const u8 *new_password, size_t new_password_len,
  	const u8 *old_password, size_t old_password_len,
  	u8 *encrypted_password_hash)
  {
  	u8 old_password_hash[16], new_password_hash[16];
  
  	if (nt_password_hash(old_password, old_password_len,
  			     old_password_hash) ||
  	    nt_password_hash(new_password, new_password_len,
  			     new_password_hash))
  		return -1;
  	nt_password_hash_encrypted_with_block(old_password_hash,
  					      new_password_hash,
  					      encrypted_password_hash);
  	return 0;
  }
  